What’s the Difference Between Sisters and Nuns?

Q: My children go to a Catholic school that is run by nuns. Or at least I always assumed they were nuns. Recently I walked by the principal while she was talking to another parent on the street, and I heard her correcting him, “No, no, we are not nuns.” I didn’t want to be rude so I just kept walking. But I wanted to stop and ask her, how can they not be nuns? They wear veils and they all live together in a convent! –Mark

A: The term nun is casually used today to refer to all women religious. But in reality, very few of the women we address as “Sister” are actually nuns.

As was mentioned in “The Priesthood and the Vow of Poverty,” the Church’s laws on religious life are extremely complicated, not only because of the huge number of different religious institutes in existence, but also because they were founded at various times in the 2000-year history of the Church for widely differing reasons. At the same time, there are very few canons in the Code of Canon Law pertaining to these institutes, since each is regulated by its own, specific proper law, approved by church authorities.

Nevertheless, it is still possible to make a few general statements about the different broad categories of women religious, which will be valid for all. As a rule, for example, all women religious make vows and live a fraternal life in common (c. 607.2). Their houses must have been established with the approval of either the diocesan bishop or of the Pope himself. (If a group of Catholic women decide independently that they wish to live celibate lives together in the same house and maintain a common prayer life, that may very well be a laudable decision, but in itself it does not make them women religious in the Church’s sense of the term.)

But while all women religious share this in common, their similarities often end right there. We all know that the members of different religious institutes engage in a wide variety of ministries. Many sisters are teachers, while a large number are nurses or are otherwise engaged in hospital ministry. Others may be employed in more humble sorts of work, as parish secretaries or housekeepers for the clergy. But no matter what these sisters are doing, they are all involved in active work in the world. One might run into them not only praying in church, but also on the street, in the grocery store or at the gas station. They live a communal life together in a convent, but can and must leave it regularly in order to perform their ordinary, daily duties.

Very different is the daily life of those women religious who embrace the contemplative life. Certain religious institutes were founded so that their members may spend their entire lives removed from the world, engaged in prayer. Those women who make permanent vows in such institutes are voluntarily agreeing to spend the rest of their lives shut away in a cloister, away from the outside world, and as a general rule they are unable ever to set foot outside their convent walls again. If cloistered women religious attend a Mass in a church that adjoins their convent, or receive visitors, there is ordinarily a metal grille that physically keeps them separated from other people.

The Church makes legal distinctions between these two basic categories of women religious. Women religious who are actively engaged in some sort of apostolate are referred to as sisters, and those who leave the world and willingly embrace the monastic life are nuns. This gets confusing because either a sister or a nun is ordinarily addressed directly as “Sister X.” Thus people tend to think that the two terms are interchangeable—but they aren’t. While a cloistered nun is called “Sister,” this does not mean that all sisters are nuns!

Canon 667.3 notes that monasteries of nuns who are wholly devoted to the contemplative life must observe what is called papal enclosure. The norms governing their cloister are actually established by the Vatican itself. On the other hand, those sisters who work out in the world—who are not nuns—still have as a rule an obligation to live in a convent, in common, but their separation from the world is not nearly so strict as that of nuns.

So what happens when a nun in a cloister breaks her leg, or needs emergency heart-bypass surgery? Under such urgent circumstances, of course, a nun is permitted to leave the cloister for the hospital—once the appropriate superior gives permission. Similarly, while nobody from the outside world is permitted to enter a cloister, superiors routinely give permission to priests who come to minister to a dying nun; doctors and other medical workers who must attend a sick nun; and plumbers, electricians, and other construction workers who have to make repairs inside the monastery. There are normally no other exceptions.

During World War II, the cloistered Poor Clare nuns in Assisi took a large number of Jewish Italians inside their cloister, to protect them from the German Nazis who had occupied that part of Italy. This was the first time that their very strict rule of enclosure had been violated since the monastery’s establishment in the 13th century! Even the Nazi soldiers (many of whom were Catholics who had been involuntarily drafted into the German army) were loathe to enter the nuns’ cloister to check for hidden refugees, and this enabled the Church to protect the Jews until arrangements could be made for their escape to safe locations outside German-held territory. Needless to say, the law of charity rightly triumphed in this case over the nuns’ proper law—but it was in fact an extraordinary technical violation of the Poor Clares’ rule, and it was done with permission of their superiors. This concrete example should give us an indication of the seriousness with which papal enclosure is regarded by the Church.

To return to Mark’s question, it is safe to say that even without knowing which religious institute the school principal belongs to, she was absolutely correct to say that she is not a nun. Any sisters working outside their convent cannot possibly be cloistered, and therefore those working in his children’s school are definitely not nuns. It is not necessarily insulting to refer to such sisters as nuns, but it is inaccurate, and the school principal was probably using the conversation with the other parent as a classic “teaching moment.”

Subscribe to Blog via Email

Enter your email address to subscribe to this blog and receive notifications of new posts by email.

Join 1,591 other subscribers

Email Address

About the author

Cathy Caridi, J.C.L., is an American canon lawyer who practices law and teaches in Rome. She founded this website to provide clear answers to canonical questions asked by ordinary Catholics, without employing all the mysterious legalese that canon lawyers know and love.
In the past Cathy has published articles both in scholarly journals and on various popular Catholic websites, including Real Presence Communications and Catholic Exchange.

Canon lawyers are not responsible for the content of canon law. The Supreme Legislator is. Only Pope Francis can change the Code of Canon Law, so if you're not happy with what the law says, please take it up with him.

NOT an ad, just a recommendation!

Catholics who are loyal to the Magisterium often come to Rome and book tours which they discover are led by persons either ignorant of, or even overtly hostile to our Church. Faithful Catholics planning a visit to Rome are encouraged to check out Catholic Custom Tours of Rome, on Facebook and also on the web at www.cctoursofrome.com